For certain types of fluid dispenser device with which it is desired to dispense fluid in the form of a fine spray, it is known to form a spray profile upstream from the spray orifice, which spray profile generally comprises a swirl chamber that is fed by one or more swirl channels. Nowadays, that type of dispenser device is widely used in a large number of fields, and in particular in the fields of pharmacy, perfumery, and cosmetic. Document EP 0 131 501 discloses a spray head for a fluid dispenser device, with a cylindrical insert of constant section inserted in the expulsion channel. The end face of the insert is perpendicular to the axis of said insert and co-operates with the end wall of the expulsion channel so as to define a spray profile comprising a swirl chamber and one or more swirl channels that connect the expulsion channel to said swirl chamber.
However, in some circumstances, that type of device may present drawbacks. Thus, ISO standard 20072, entitled “Aerosol drug delivery device design verification”, includes a chapter relating to the ability to withstand impacts, commonly known as “drop tests”. In summary, the test requires the dispenser device to be dropped from a height of at least 1 meter (m), in three starting orientations, with and without a protective cap. The risk of dropping the spray head appears very clearly as one of the main risks for the integrity of the dispenser device. Although the center of gravity of dispenser devices generally causes it to turn while dropping, the risk of impact on the axis of the spray head is probable. From experience, that type of impact generally causes changes in the interference between the inner nozzle and the swirl chamber. In particular, the inner nozzle may either move away from the spray profile, or, on the contrary, may compress it, preventing said spray profile from subsequently operating in reliable manner, resulting in poor spray quality.
Another problem that may occur with inner nozzles relates to the mechanical stresses between the components. Such stresses, in particular in materials of the polyolefin type, may lead to a phenomenon of creep and thus to a change in the shape of the spray profile over time, with a loss of spray quality.
Documents EP 0 815 946, U.S. Pat. No. 5,439,178, GB 2 007 807, U.S. Pat. No. 3,490,658, U.S. Pat. No. 5,622,318, EP 0 930 102, and U.S. Pat. No. 4,989,790 describe prior-art devices.